[U-Boot] [PATCH 3/5] Add fuse API and commands

[Stefano Babic]

On 14/08/2012 14:52, Benoît Thébaudeau wrote:
> This can be useful for fuse-like hardware, OTP SoC options, etc.
> 
> Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau at advansee.com>
> Cc: Wolfgang Denk <wd at denx.de>
> Cc: Stefano Babic <sbabic at denx.de>
> ---

CC to Anatolji, he knows very well the MPC5121 that has currently
support of fuses.

>  {u-boot-4d3c95f.orig => u-boot-4d3c95f}/README     |    1 +
>  .../common/Makefile                                |    1 +
>  /dev/null => u-boot-4d3c95f/common/cmd_fuse.c      |  182 ++++++++++++++++++++
>  .../include/config_cmd_all.h                       |    1 +
>  /dev/null => u-boot-4d3c95f/include/fuse.h         |   49 ++++++
>  5 files changed, 234 insertions(+)
>  create mode 100644 u-boot-4d3c95f/common/cmd_fuse.c
>  create mode 100644 u-boot-4d3c95f/include/fuse.h
> 
> diff --git u-boot-4d3c95f.orig/README u-boot-4d3c95f/README
> index fb9d904..c40fd34 100644
> --- u-boot-4d3c95f.orig/README
> +++ u-boot-4d3c95f/README
> @@ -780,6 +780,7 @@ The following options need to be configured:
>  		CONFIG_CMD_FDOS		* Dos diskette Support
>  		CONFIG_CMD_FLASH	  flinfo, erase, protect
>  		CONFIG_CMD_FPGA		  FPGA device initialization support
> +		CONFIG_CMD_FUSE		  Device fuse support
>  		CONFIG_CMD_GO		* the 'go' command (exec code)
>  		CONFIG_CMD_GREPENV	* search environment
>  		CONFIG_CMD_HWFLOW	* RTS/CTS hw flow control

Agree in this split: we have a general fuse command and each SOC / SOC
family can add its own implementation.

> +static int do_fuse(cmd_tbl_t *cmdtp, int flag, int argc, char *const argv[])
> +{
> +	u32 bank, row, bit, cnt, val;
> +	int ret, i;
> +
> +	if (argc < 4 || strtou32(argv[2], 0, &bank) ||
> +			strtou32(argv[3], 0, &row))
> +		return CMD_RET_USAGE;
> +
> +	if (!strcmp(argv[1], "read.bit")) {
> +		if (argc != 5 || strtou32(argv[4], 0, &bit))
> +			return CMD_RET_USAGE;
> +
> +		printf("Reading bank %u row 0x%.8x bit %u: ", bank, row, bit);
> +		ret = fuse_read_bit(bank, row, bit, &val);
> +		if (ret)
> +			goto err;
> +
> +		printf("%u\n", val);
> +	} else if (!strcmp(argv[1], "read.row")) {
> +		if (argc == 4)
> +			cnt = 1;
> +		else if (argc != 5 || strtou32(argv[4], 0, &cnt))
> +			return CMD_RET_USAGE;
> +
> +		printf("Reading bank %u:\n", bank);
> +		for (i = 0; i < cnt; i++, row++) {
> +			if (!(i % 4))
> +				printf("\nRow 0x%.8x:", row);
> +
> +			ret = fuse_read_row(bank, row, &val);
> +			if (ret)
> +				goto err;
> +
> +			printf(" %.8x", val);
> +		}
> +		putc('\n');
> +	} else if (!strcmp(argv[1], "sense.bit")) {
> +		if (argc != 5 || strtou32(argv[4], 0, &bit))
> +			return CMD_RET_USAGE;
> +
> +		printf("Sensing bank %u row 0x%.8x bit %u: ", bank, row, bit);

Each command sends this output to the console. I am thinking about if
instead of printf() we shoud use debug()

> +U_BOOT_CMD(
> +	fuse, CONFIG_SYS_MAXARGS, 0, do_fuse,
> +	"Fuse sub-system",
> +	     "read.bit <bank> <row> <bit> - read a fuse bit\n"
> +	"fuse read.row <bank> <row> [<cnt>] - read 1 or 'cnt' fuse rows,\n"
> +	"    starting at 'row'\n"
> +	"fuse sense.bit <bank> <row> <bit> - sense a fuse bit\n"
> +	"fuse sense.row <bank> <row> [<cnt>] - sense 1 or 'cnt' fuse rows,\n"
> +	"    starting at 'row'\n"
> +	"fuse prog.bit <bank> <row> <bit> - program a fuse bit (PERMANENT)\n"
> +	"fuse prog.row <bank> <row> <hexval> [<hexval>...] - program 1 or\n"
> +	"    several fuse rows, starting at 'row' (PERMANENT)\n"
> +	"fuse ovride.bit <bank> <row> <bit> <val> - override a fuse bit\n"
> +	"fuse ovride.row <bank> <row> <hexval> [<hexval>...] - override 1 or\n"
> +	"    several fuse rows, starting at 'row'"
> +);

General question: why do we need the "bit" interface ? I have thought it
is enough the read row / prog row interface (even if there is a bit
programming).

Best regards,
Stefano Babic

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